Propel type mechanical pencil



B. D. SMITH PROFEL TYPE MECHANICAL PENC IL July 3o, 1957 2 Sheets-Sheet l Filed June 4, 1954 IN V EN T 5 9.' 0R' BY n. ,9A/(HARD o. .SMITH In Y 4 JTOR/YEVJ nited States Patent PROPEL TYPE MECHANICAL PENCIL Blanchard D. Smith, Atlanta, Ga., assignor to Scripto, Inc., Atlanta, Ga., a corporation of Georgia Application .lune 4, 1954, Serial No. 434,506

7 Claims. (Cl. 120-18) This invention relates to mechanical pencils, and more particularly to such pencils of the propel or non-retracting type, in which the lead is fed simply by abutment at its rear end with a propelling member, and a restraining friction grip on the lead is characteristically provided for adjacent the writing end of the pencil to maintain the abutting relation `of the lead with the propelling member as it is fed.

The great advantage of a propel pencil is that the writing lead is more closely confined for support within the receiving or lead guide tube, because the guide tube does not have to be enlarged beyond the lead diameter to provide operating clearance for a clut-ch element to grip the rear end of the lead. As a result, propel type pencils are better adapted for handling fine leads. Also, with any type of lead, the operation of a propel pencil is not substantially affected by mid-length breaking of a contained lead, because the front lead piece will still be restrained by the writing end friction grip and will continue to feed i normally until used up.

A propel pencil has several important disadvantages, however, that have substantially hampered its general acceptance in the mechanical pencil field. In the first place, the writing end friction grip is commonly obtained by means Vof a split tube or point arrangement of some sort, which is difficult to arrange for continued eective gripping of the lead over an extended period, and which further has a tendency to scratch and weaken the lead as it issues at the writing point. In addition, and most importantly, the usual writing end friction grip arrangement prevents easy insertion of a new lead when necessary, for the new lead must be inserted from the writing end of the pencil (unless the feed mechanism is disassembled for rear end insertion), and writing end insertion requires the lead to be pushed reversely through the friction grip, which cannot be readily done if the friction grip is arranged for effective action during feeding of the lead.

According to the present invention, an improved propel pencil arrangement is provided in which the foregoing disadvantages are eliminated by means of a lead support tube that is yieldably biased forwardly in the pencil to have the forward end thereof normally compressed for frictionally gripping the lead nicely during feeding, but which may be displaced rearwardly in the pencil when desired to relieve the compression at the forward end so that a new lead is freely received therein.

This arrangement and other features of the propel pencil of the present invention vare described in detail below in connection with the accompanying drawings, in which:

Fig. 1 is a central longitudinal section of a propel pencil embodying the present invention;

Fig. 2 is an enlarged fragmentary sectional detail of the Writing end of the pencil shown in Fig. l;

Fig. 3 is a sectional detail taken substantially on the line 3 3 in Fig. l;

Fig. 4 is a sectional detail taken substantially on the line 4-4 in Fig. l; I

Fig. 5 is a sectional detail taken substantially on the line 5 5 in Fig. l;

Fig. 6 is a sectional detail taken substantially on' the line 6-6 in Fig. l;

Fig. 7 is a greatly enlarged fragmentary sectional' detail of the writing tip of the pencil in which the normal disposition of the liner tube for frictionally gripping the writing lead is illustrated; and

Fig. 8 is a corresponding enlarged fragmentary sectional detail in which the liner tube is shown rearwardly displaced to release the friction grip thereof.

The propel pencil shown in the drawings comprises a barrel lili, preferably a barrel of plastic material, fitted with a fixed metal writing tip portion 12 and assembled rearwardly with a rotatable metal operating cap or sleeve 14.

The barrel 1l) is formed from its rear end with a main bore 16 that extends forwardly for a major portion of the barrel length to a short tapered section at 18 which` leads to a short bore 2l) of reduced diameter terminating at an annular shoulder 22, and which is provided for a purpose that will be explained presently. VBeyond the annular shoulder 22, the barrel 1t) tapers internally to a terminal bore 24 in which a shank portion 26 of the writing tip 12 is press fitted and thereby attached in fixed relation to the barrel lil.

The writing tip l2 is in turn formed from its rear end with three stepped bores 28, 30 and 32. The first rearwardly opening bore 28 is the one of largest size or diameter, and it receives a longitudinally slotted guide tube 34 which is fixed to the writing tip 12, as by dimpling of the writing tip shank portion 26 at 36. The intermediate writing tip bore 30 receives slidably therein the forward end of a longitudinally slotted liner or lead support tube 3S that extends slidably within the guide tube 34. This intermediate bore 30 terminates in a forwardly tapering conical shoulder 40 leading to the terminal writing tip bore 32, which is of lead size diameter and through which the lead issues freely for writing.

The longitudinally slotted guide tube 34, that is fixed to or anchored in the Writing tip 12 at the forward end of the barrel 10 as noted above, extends rearwardly through the barrel 10 and within the previously mentioned operating sleeve 14 in an extent exceeding that of a helix feed member 42 assembled thereon for relative rotation. This helix member 42, which like the barrel 10 is preferably formed of plastic material, has a large diameter rear portion 44 fitting ythe operating sleeve 14 as la plug, and to which the operating sleeve 14 is fixed, as by a rearwardly facing slit boss 46.

Within the barrel 10, the helix member 42 extends forwardly in spaced relation through the main bore 16, and is seated for rotation therein by means of a flanged thrust collar 48 keyed as at 48 on its forward end to ride a longitudinally slit friction band 54) keyed as at 50 within rthe previously mentioned short, reduced diameter, barrel bore 20 and bottomed on the annular shoulder 22 at which this short bore 2t) terminates forwardly. As a result, the helix member 42 is arranged to be rotated in the barrel 10 by means of the operating sleeve 14'to which it is fixed, the sleeve 14 being telescoped over a short rear barrel portion of reduced diameter, as at 10', for alignment therewith.

The helix member 42 and operating sleeve 14 are maintained in assembled relation with the barrel 10 for rotation in this manner by means of ears 52 struck outwardly adjacent the rear end of guide tube 34 opposite t-he longitudinal slot therein to overlie a retaining washer 54 stacked on a thrust Washer 56 bearing 'against the rear face of helix member 42. The retaining washer 54 is specially formed with a finger portion 54" extending inwardly through the longitudinal slot 34 of the guide tube 34 to 'contain therein a compression spring 58 bottomed on a lateral lip 60 formed at the rear end of the liner tube 38 so as normally to bias the liner tube 38 forwardly in the guide tube 34.

This forward bias results, under normal writing conditions, in urging the liner tube 38 against the conical writing tip shoulder 40, and as the liner tube 38 is longitudinally slotted, as seen at 38', its forward end is compressed by the conical shoulder 40 to grip frictionally a writing lead L slidably disposed therein for feeding through the terminal writing tip bore 32 (as shown best in Fig. 7). The forward end of the liner tube 3,8, is also preferably formed with a longitudinal notch or slit 62, opposite the longitudinal slot 38', for facilitating application of the lead gripping compression from the conical shoulder 40.

The slidably contained writing lead L extends rearwardly in the liner tube 38 for endwise abutment with the forward end of a propelling member 64, which is also slidably disposed in the liner tube 38 and is formed with a lateral lug portion 66 extending through the longitudinal slots 38 and 34 of the liner tube 38 and guide tube 34 to engage the feed threads 68 of the helix member 42 for lead feeding actuation thereby. Forward actuation of the propelling member 64 results in feeding the writing lead L with the forward end of the liner tube 38 biased to exert the frictional gripping action previously described.

It should be further noted, however, that the lateral lip 60 at the rear end of the liner tube 38 forms a closure by which the propelling member 64 is confined at this end within the liner tube 38, so that by rearward actuation of the propellingV member 64 it can be disposed in abutment with the liner tube closure lip 60 and employed to displace the liner tube 38 rearwardly against the bias exerted thereon by the spring 58. Such rearward displacement of the liner tube 38 results in removing its forward end from the conical writing tip shoulder 40 (see Fig. 8), and thereby releasing the lead gripping compression to allowl insertion of a new writing lead L through the forward end of the liner tube 38 just as easilyvas it is received in the remainder ofthe liner tube 38.

In addition, a comparable result can be obtained, in the event it is desired to insert only a short length of writing lead L, by simply pushing an end of the short lead L against the forward end of the liner tube 38, as only a relatively light yieldable bias from the spring 58 is necessary to dispose the liner tube 38 for operation as described above, and the liner tube 38 is accordingly readily displaced rearwardly in this manner', too, to receive a new writing lead L.

Otherwise, the propel pencil ofthe present invention may be arranged with any of the usual accessories desired, such as Ya pocket clip, 70. andV jacketed. eraser 72 assembled with the operating sleeve as shown. Also, a magazine for extra reserve leads X may be arranged for access upon removal of the jacketed eraser 72 by means of aligned arcuate slots 44 and continuing grooves 42' in the rear large portion 44 and remaining forward body, respectively, of the helix member 42.

The present invention has been described in detail above for purposes of illustration only and is rnot intended to be limitedy by this description or otherwise except as defined in the appended claims.

I claim: fi

1. In a mechanical pencil of the propel type incorporating a barrel, a helix feed member rotatably housed in saidY barrel and a longitudinally slotted guide tube disposed within said helix member and anchored to said barrel against rotation, the improvement which comprises a longitudinally slotted liner tube slidably disposed within said guide tube for slidably holding a lead as it is fed by said helix member for writing, yieldable means normally biasing said liner tube forwardly in said guide tube, and means compressing the forward end of said liner tube for frictionally gripping a lead slidably held therein when said tube is normally positioned by the yieldable bias thereon, said liner tube being removable from said compressing means for insertion of a lead therein by rearward displacement in said guide tube against said yieldable bias.

2. In a mechanical pencil of the propel type, a barrel, a helix feed member rotatably housed in said barrel, a longitudinally slotted guide tube disposed within said helix member and anchored to said barrel against rotation, a longitudinally slotted liner tube slidably disposed within said guide tube for slidably holding a lead as it is fed for writing, yieldable means confined within said guide tube for ynormally biasing said liner tube forwardly therein, a lead propelling member slidably disposed within said liner tube and formed with a lateral lug portion extending through the longitudinal slots of said liner tube and said guide tube and engaging said helix member for lead feeding actuation thereby, said barrel having a writing end portion formed with a first bore of liner tube size in diameter, said first bore terminating short of the barrel writing end tip at a forwardly tapering shoulder and a second bore of lead size in diameter continuing from said shoulder and opening at said writing end tip, and said liner tube having the forward end thereof slidably extending within said first bore and normally bottomed on said tapered shoulder by said yieldable bias but displaceable rearwardly from said shoulder against said yieldable bias.

3. In a mechanical pencil of the propel type, the structure defined in claim 2 and further characterized in that the rear end of said liner tube is formed with a lateral closure lip, whereby said liner tube is displaceable rearwardly by rearward actuation of said propelling member in contact with said closure lip.

4. In a mechanical pencil of the propel type, the structure defined in claim 2 and further characterized in that said guide tube is anchored to said barrel adjacent the forward barrel end and extends rearwardly beyond said helix member, and the rearwardly extending end of said guide tube carries retaining means confining said helix member rotatably within said barrel.

5. In a mechanical pencil of the propel type, the structure defined in claim 4 and further characterized in that said retaining means also serves for confining said yieldable means within said guide tube and against the rear end of said liner tube.

6. A mechanical pencil having a barrel, a helix feed member rotatably housed in said barrel, a longitudinally slotted guide tube disposed within said helix member and anchored to said barrel against rotation, a longitudinally slotted liner tube slidably disposed within said guide tube, yieldable means at the rear end of said liner tube normally biasing said liner tube forwardly, and means compressing the forward end of said liner tube for gripping a lead therein when said liner tube is normally positioned by the yieldable bias thereon, said liner tube being removable from said compressible means for insertion of a lead therein by rearward displacement in said guide tube against said yieldable bias.

7. A mechanical pencil having a barrel, a helix feed member rotatably housed in said barrel, a longitudinally slotted guide tube disposed within said helix member and anchored to said barrel against rotation, a longitudinally slotted liner tube slidably disposed within said guide tube, yieldable means at the rear end of said liner tube normally biasing said liner tube forwardly, a lead propelling member slidably disposed within saidV liner tube and having a lateral lug portion extending through the longitudinal slots of said liner tube and said guide tube for engaging said helix member, and means compressing the forward end of said linertube for gripping a lead therein when said liner tube is normally positioned by the yieldable bias thereon, said liner tube being removable from said compressible means for insertion of a lead therein by rearward displacement in said guide tube against said yieldable bias. 5

References Cited in the le of this patent UNITED STATES PATENTS 1,063,189 Dutton June 3, 1913 10 Lindberg Oct. l, 1929 Savoie Jan. 5, 1932 Blake Jan. 25, 1938 Savoie Dec. 13, 1949 FOREIGN PATENTS Great Britain Dec. 6, 1923 

